CN113366273A

CN113366273A - Refrigerating device

Info

Publication number: CN113366273A
Application number: CN201980090546.1A
Authority: CN
Inventors: 石川智隆; 石原宽也; 野本宗
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2019-02-05
Filing date: 2019-02-05
Publication date: 2021-09-07
Also published as: EP3922927A1; JPWO2020161804A1; WO2020161804A1; EP3922927A4

Abstract

A refrigeration device (100) is provided with a refrigerant circuit in which a refrigerant circulates in the order of a compressor (1), a first heat exchanger (2), an expansion device (3), and a second heat exchanger (4), and a drain pan (5) disposed below the second heat exchanger (4). The refrigeration device has, as operation modes, a refrigeration mode in which cooling is performed using the second heat exchanger (4), a first defrosting mode in which the second heat exchanger (4) is heated, and a second defrosting mode in which the drain pan (5) is heated. In addition to the first defrosting mode for defrosting the second heat exchanger (4), a second defrosting mode for heating the drain pan (5) is provided, so that the cooling by the second heat exchanger (4) can be promptly restarted while promoting the drainage from the drain pan (5).

Description

Refrigerating device

Technical Field

The present invention relates to a refrigeration apparatus.

Background

A defrosting mode for melting frost attached to an evaporator is provided in a refrigeration apparatus. For example, japanese patent application laid-open No. 5-126440 (patent document 1) discloses a refrigeration apparatus capable of heating a drain pan during defrosting of an evaporator in a refrigeration apparatus of a reverse hot-gas defrosting method.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 5-126440

Disclosure of Invention

Problems to be solved by the invention

In the above-mentioned japanese patent application laid-open No. 5-126440 (patent document 1), the drain pan is heated during defrosting in order to melt water or ice pieces falling from the evaporator to the drain pan. However, even when defrosting of the evaporator is completed, if ice remains on the drain pan, there is a possibility that drainage from the drain pan is hindered, and it is not suitable to end the defrosting mode. On the other hand, if the defrosting mode is continued, the inside of the tank cannot be cooled by the evaporator, and the temperature in the tank rises. Therefore, in the case where defrosting of the evaporator has been completed, it is preferable to promptly restart cooling by the evaporator.

The present invention has been made to solve the above-described problems, and an object thereof is to provide a refrigeration apparatus capable of quickly restarting cooling by an evaporator while promoting drainage from a drain pan.

Means for solving the problems

The present disclosure relates to a refrigeration device. A refrigeration device is provided with: a refrigerant circuit that circulates a refrigerant in the order of a compressor, a first heat exchanger, an expansion device, and a second heat exchanger; and a drain pan disposed below the second heat exchanger. The refrigeration apparatus has, as operation modes, a refrigeration mode in which cooling is performed using the second heat exchanger, a first defrost mode in which the second heat exchanger is heated, and a second defrost mode in which the drain pan is heated.

Effects of the invention

According to the refrigeration apparatus of the present disclosure, since the second defrosting mode for heating the drain pan is provided in addition to the first defrosting mode for defrosting the second heat exchanger, it is possible to quickly restart cooling by the second heat exchanger while promoting drainage from the drain pan.

Drawings

Fig. 1 is a diagram showing the configuration of a refrigeration apparatus according to embodiment 1.

Fig. 2 is a diagram showing a configuration of the control device 10 that controls the refrigeration apparatus.

Fig. 3 is a flowchart for explaining control executed by the control device in embodiment 1.

Fig. 4 is a flowchart for explaining details of the defrosting process of the drain pan performed in step S4 of fig. 3.

Fig. 5 is a diagram showing the configuration of a refrigeration apparatus according to embodiment 2.

Fig. 6 is a diagram showing the flow of the refrigerant in the first defrosting mode in the refrigeration apparatus according to embodiment 2.

Fig. 7 is a flowchart for explaining control executed by the control device in embodiment 2.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Hereinafter, a plurality of embodiments will be described, but it is expected from the beginning of the application that the configurations described in the respective embodiments are appropriately combined. In the drawings, the same or corresponding portions are denoted by the same reference numerals, and description thereof will not be repeated.

Embodiment mode 1

Fig. 1 is a diagram showing the configuration of a refrigeration apparatus according to embodiment 1. Referring to fig. 1, the refrigeration apparatus 100 includes a refrigerant circuit in which a refrigerant circulates in the order of a compressor 1, a first heat exchanger 2, an expansion device 3, and a second heat exchanger 4, and a drain pan 5 disposed below the second heat exchanger 4. In normal operation of the refrigeration apparatus (cooling mode), the first heat exchanger 2 operates as a condenser, and the second heat exchanger 4 operates as an evaporator (also referred to as a cooler). As the expansion device 3, an electronic expansion valve whose opening degree can be changed may be used, but a temperature type automatic expansion valve, a capillary tube whose opening degree is fixed, or the like may be used.

The refrigeration apparatus 100 further includes a defrosting heater 6 that heats the second heat exchanger 4, a fan 7 that sends air to the first heat exchanger 2, and a temperature sensor 30 that detects the temperature of the refrigerant.

The compressor 1, the first heat exchanger 2, the fan 7, and the controller 11 are disposed in the outdoor unit 101. Further, a pipe 28 connected to the suction port of the compressor 1, a pipe 21 connecting the discharge port of the compressor 1 to the refrigerant inlet of the first heat exchanger 2, and a pipe 22 connecting the refrigerant outlet of the first heat exchanger 2 are disposed in the outdoor unit 101.

The expansion device 3, the second heat exchanger 4, the heater 6, the drain pan 5, and the controller 12 are disposed in the indoor unit 102. Further, a pipe 24 connected to the refrigerant inlet of the expansion device 3, a pipe 25 connecting the refrigerant outlet of the expansion device 3 to the refrigerant inlet of the second heat exchanger 4, and a pipe 26 connecting the refrigerant outlet of the second heat exchanger 4 are disposed in the indoor unit 102.

The outdoor unit 101 and the indoor units 102 are connected by

extension pipes

23 and 27. An extension pipe 23 connects the pipe 22 and the pipe 24. An extension pipe 27 connects the pipe 26 and the pipe 28.

In addition, in the case where the refrigeration apparatus is not separated into the outdoor unit and the indoor unit, the extension pipe may not be provided, and in this case, the components shown in fig. 1 may be housed in 1 casing as in a household refrigerator.

In the present embodiment, the controller 11 and the controller 12 cooperate with each other as the controller 10 to control the compressor 1, the fan 7, the expansion device 3, and the heater 6.

Fig. 2 is a diagram showing a configuration of the control device 10 that controls the refrigeration apparatus. Referring to fig. 2, the control section 11 includes a processor 41, a memory 42, and a communication interface 43. The communication interface 43 is a device for communicating with the control unit 12. The processor 41 controls the operating frequency of the compressor 1 and the rotational speed of the fan 7 in accordance with the data stored in the memory 42 and the information obtained from the control unit 12 via the communication interface 43.

The control unit 12 includes a communication interface 53 that receives a transmission signal from the control unit 11, a processor 51, and a memory 52.

The

memories

42 and 52 are configured to include, for example, a ROM (Read Only Memory), a RAM (Random Access Memory), and a flash Memory. In addition, an operating system, an application program, and various data are stored in the flash memory. The processor 51 controls the heater 6 and the expansion device 3.

The control device 10 shown in fig. 2 is realized by the

processors

41 and 51 executing the operating system and the application program stored in the

memories

42 and 52, respectively. When the application is executed, various data stored in the

memories

42 and 52 are referred to. When there are a plurality of indoor units, the control unit 12 is provided in each of the plurality of indoor units. In such a case, the processors of the plurality of control units cooperatively perform the overall control of the refrigeration apparatus 100.

The refrigeration apparatus of the present embodiment has, as operation modes, a refrigeration mode in which cooling is performed using the second heat exchanger 4, a first defrost mode in which the second heat exchanger 4 is heated, and a second defrost mode in which the drain pan 5 is heated. In addition, the second defrost mode is to melt the frost of the drain pan 5 and to heat the ice cubes or water dropped from the second heat exchanger 4 to the drain pan 5 to promote the drainage.

The pipe 24 connecting the first heat exchanger 2 and the expansion device 3 is configured to exchange heat with the drain pan 5. For example, a part of the routed pipe 24 is disposed inside or outside the drain pan 5 so as to be in contact with the bottom surface of the drain pan 5 in a state where heat conduction with the bottom surface of the drain pan 5 is possible.

In the first defrosting mode, the control device 10 operates the heater 6. To facilitate defrosting, it is preferable to stop the compressor 1 in the first defrosting mode to avoid evaporation of the refrigerant in the second heat exchanger 4 from occurring. Therefore, in the first defrosting mode, the cooling in the tank by the second heat exchanger 4 is interrupted.

On the other hand, in the second defrosting mode, the controller 10 sets the rotation speed of the fan 7 in the second defrosting mode to be lower than the rotation speed of the fan 7 in the cooling mode while the compressor 1 is operated while the heater 6 is not operated. By performing such control, the amount of heat radiation from the refrigerant in the first heat exchanger 2 decreases, and the temperature of the refrigerant in the pipe 24 that exchanges heat with the drain pan 5 increases compared to the temperature of the refrigerant in the cooling mode. Thereby, while the in-tank cooling of the second heat exchanger 4 is maintained to some extent, the defrosting in the drain pan 5 is promoted as compared with the normal cooling mode.

Fig. 3 is a flowchart for explaining control executed by the control device in embodiment 1. The processing of this flowchart is repeatedly executed every time a certain time elapses or every time a preset condition is satisfied during the operation of the refrigeration apparatus. Referring to fig. 1 and 3, in step S1, the controller 10 determines whether or not defrosting of the second heat exchanger 4 (cooler) is necessary. For example, when defrosting is performed at regular intervals, the control device 10 determines in step S1 based on whether or not a fixed time has elapsed since the last defrosting of the cooler. The determination at step S1 may be performed based on the detected refrigerant temperature or the adhesion state of frost on the cooler.

When defrosting of the second heat exchanger 4 (cooler) is required (yes in S1), the refrigeration apparatus 100 operates in the first defrosting mode. Specifically, in step S2, the controller 10 turns on the heater 6 to heat the second heat exchanger 4. Thereby, the frost adhering to the second heat exchanger 4 is melted.

On the other hand, when defrosting of the second heat exchanger 4 (cooler) is not necessary (no in S1), the controller 10 determines whether defrosting of the drain pan 5 is necessary in step S3.

When defrosting of the drain pan 5 is required (yes in S3), the refrigeration apparatus 100 operates in the second defrosting mode. At this time, the control device 10 performs the defrosting process of the drain pan 5 in step S4. On the other hand, if defrosting of the drain pan 5 is not necessary (no in S3), the controller 10 performs operation in the cooling mode as normal operation in step S5.

Fig. 4 is a flowchart for explaining details of the defrosting process of the drain pan performed in step S4 of fig. 3. When the defrosting process of the drain pan is started, the control device 10 determines whether or not the refrigerant temperature T passing through the tube 24 detected by the temperature sensor 30 is lower than a determination value in step S11.

If the refrigerant temperature T is lower than the determination value (yes in S11), the control device 10 decelerates the rotation of the outdoor unit fan 7 in step S12 because the refrigerant temperature T needs to be increased to defrost the drain pan 5. Thereby, the pressure of the high-pressure portion of the refrigerant rises, and the temperature T of the refrigerant rises. In step S12, instead of decelerating the rotation of the fan 7, the operating frequency of the compressor 1 may be increased.

When the refrigerant temperature T is equal to or higher than the determination value (no in S11), the refrigerant temperature has reached a temperature suitable for defrosting, and therefore, the refrigerant cycle is continued in this state, and in step S13, the controller 10 determines whether defrosting of the drain pan 5 is completed. If defrosting is not completed (no in S13), the process returns to step S11 again to continue defrosting. On the other hand, if defrosting has been completed (yes in S13), the process proceeds to the flowchart of fig. 3 in step S14.

As described above, in embodiment 1, the second defrosting mode is provided in which only the drain pan 5 is defrosted in addition to the second heat exchanger 4 (cooler).

That is, in the first defrosting mode, the second heat exchanger 4 (cooler) performs defrosting using heat from the heater 6. In the second defrosting mode, the heating by the heater 6 is stopped, the rotation of the fan 7 is slowed or stopped, or the operating frequency of the compressor 1 is increased, so that the temperature of the refrigerant to the drain pan 5 is increased.

As a result, although the Coefficient Of Performance (COP) Of the refrigeration apparatus is slightly reduced, the inside Of the tank can be cooled by the second heat exchanger 4 (cooler) while defrosting only the drain pan 5 is performed, and therefore, even when defrosting or draining Of the drain pan 5 takes time, cooling Of the inside Of the tank can be maintained.

Embodiment mode 2

In embodiment 1, in the first defrosting mode, the heater 6 is used for defrosting the second heat exchanger 4. In contrast, in embodiment 2, in the first defrosting mode, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 is introduced into the second heat exchanger 4.

Fig. 5 is a diagram showing the configuration of a refrigeration apparatus according to embodiment 2. Referring to fig. 5, the refrigeration apparatus 200 includes a refrigerant circuit in which a refrigerant circulates in the order of the compressor 1, the first heat exchanger 2, the expansion device 3, and the second heat exchanger 4, and a drain pan 5 disposed below the second heat exchanger 4. In normal operation of the refrigeration apparatus (cooling mode), the first heat exchanger 2 operates as a condenser, and the second heat exchanger 4 operates as an evaporator (also referred to as a cooler). As the expansion device 3, an electronic expansion valve whose opening degree can be changed may be used, but a temperature type automatic expansion valve, a capillary tube whose opening degree is fixed, or the like may be used.

The refrigeration apparatus 200 further includes a four-way valve 207 that changes the circulation direction of the refrigerant, a fan 7 that sends air to the first heat exchanger 2, and a temperature sensor 30 that detects the temperature of the refrigerant.

The compressor 1, the first heat exchanger 2, the fan 7, and the controller 211 are disposed in the outdoor unit 201. A pipe 228 connecting the four-way valve 207 to the extension pipe 27, a pipe 229 connecting the four-way valve 207 to the suction port of the compressor 1, a pipe 221 connecting the discharge port of the compressor 1 to the four-way valve 207, a pipe 222 connecting the four-way valve 207 to the refrigerant inlet of the first heat exchanger 2, and a pipe 22 connecting the refrigerant outlet of the first heat exchanger 2 are further disposed in the outdoor unit 101.

The expansion device 3, the second heat exchanger 4, the drain pan 5, and the controller 212 are disposed in the indoor unit 202. Further, a pipe 24 connected to the refrigerant inlet of the expansion device 3, a pipe 25 connecting the refrigerant outlet of the expansion device 3 to the refrigerant inlet of the second heat exchanger 4, and a pipe 26 connecting the refrigerant outlet of the second heat exchanger 4 are disposed in the indoor unit 202.

The outdoor unit 201 and the indoor unit 202 are connected by

extension pipes

23 and 27. An extension pipe 23 connects the pipe 22 and the pipe 24. The extension pipe 27 connects the pipe 26 and the pipe 228.

In addition, in the case where the refrigeration apparatus is not separated into the outdoor unit and the indoor unit, the extension pipe may not be provided, and in this case, the components shown in fig. 5 may be housed in 1 casing as in a household refrigerator.

In the present embodiment, the control unit 211 and the control unit 212 cooperate as the control device 210 to control the compressor 1, the fan 7, the expansion device 3, and the four-way valve 207. The control unit 211, the control unit 212, and the control device 210 can have the same configurations as the control unit 11, the control unit 12, and the control device 10 shown in fig. 2.

In the cooling mode and the second defrosting mode, four-way valve 207 is set so that pipe 221 communicates with pipe 222 and pipe 228 communicates with pipe 229 as indicated by solid lines in fig. 5. As a result, in the cooling mode and the second defrost mode, the refrigerant circulates in the direction indicated by the arrow in fig. 5.

Fig. 6 is a diagram showing the flow of the refrigerant in the first defrosting mode in the refrigeration apparatus according to embodiment 2. Referring to fig. 6, in the first defrosting mode, four-way valve 207 is set to communicate between pipe 221 and pipe 228 and between pipe 222 and pipe 229 as indicated by the solid line in fig. 6. As a result, in the first defrost mode, the refrigerant circulates in the direction indicated by the arrow of fig. 6.

That is, the four-way valve 207 is configured to change the circulation direction of the refrigerant in the refrigerant circuit to the reverse direction of the circulation of the compressor 1, the second heat exchanger 4, the expansion device 3, and the first heat exchanger 2 in this order, which is opposite to the forward direction, in the first defrosting mode.

In the refrigeration apparatus according to embodiment 2, the four-way valve 207 is set such that the refrigerant circulation direction is in the positive direction in the cooling mode. At this time, the first heat exchanger 2 operates as a condenser, and the second heat exchanger 4 operates as an evaporator.

On the other hand, in the first defrosting mode, the four-way valve 207 is set so that the refrigerant circulation direction is reversed. At this time, the first heat exchanger 2 operates as an evaporator, and the second heat exchanger 4 operates as a condenser, so that cooling in the tank cannot be continued and is temporarily interrupted.

In contrast, in the second defrosting mode, the four-way valve 207 is set such that the refrigerant circulation direction is in the positive direction. The pipe 24 connected between the first heat exchanger 2 and the expansion device 3 is configured to exchange heat with the drain pan 5 in the refrigeration apparatus 200 according to embodiment 2, similarly to the refrigeration apparatus 100 according to embodiment 1.

The rotation speed of the fan 7 in the second defrosting mode is set to be lower than the rotation speed of the fan 7 in the cooling mode. Therefore, the temperature of the refrigerant flowing through the pipe 24 rises, and heating of the drain pan 5 is promoted.

Fig. 7 is a flowchart for explaining control executed by the control device in embodiment 2. The processing of this flowchart is repeatedly executed every time a certain time elapses or every time a preset condition is satisfied during the operation of the refrigeration apparatus. Referring to fig. 5 and 7, in step S1, the controller 210 determines whether or not defrosting of the second heat exchanger 4 (cooler) is necessary. For example, when defrosting is performed at regular intervals, the controller 210 determines in step S1 based on whether or not a fixed time has elapsed since the last defrosting of the cooler. The determination at step S1 may be performed based on the detected refrigerant temperature or the adhesion state of frost on the cooler.

When defrosting of the second heat exchanger 4 (cooler) is necessary (yes in S1), the refrigeration apparatus 200 operates in the first defrosting mode. Specifically, in step S2A, the control device 210 sets the four-way valve 207 as shown in fig. 6, and circulates the refrigerant in the reverse direction indicated by the arrow in fig. 6. As a result, the high-temperature gas refrigerant from the compressor 1 flows into the second heat exchanger 4, and therefore frost adhering to the second heat exchanger 4 melts.

On the other hand, when defrosting of the second heat exchanger 4 (cooler) is not necessary (no in S1), the controller 210 determines whether defrosting of the drain pan 5 is necessary in step S3.

When defrosting of the drain pan 5 is required (yes in S3), the refrigeration apparatus 200 operates in the second defrosting mode. At this time, the control device 210 performs the defrosting process of the drain pan 5 in step S4. In the second defrost mode, the refrigerant flows in the direction indicated by the arrow of fig. 5. The details of the second defrost mode are as described in the flowchart of fig. 4, and therefore, the description thereof will not be repeated here.

On the other hand, if defrosting of the drain pan 5 is not necessary (no in S3), the controller 210 performs operation in the cooling mode as normal operation in step S5. In the cooling mode, the refrigerant flows in the direction indicated by the arrow in fig. 5.

As described above, in embodiment 2, as in embodiment 1, a second defrosting mode is provided in which only the drain pan 5 is defrosted except for the second heat exchanger 4 (cooler).

That is, in the first defrosting mode, the second heat exchanger 4 (cooler) uses the heat of the high-temperature and high-pressure gas refrigerant to defrost by reversing the refrigerant circulation direction by the four-way valve 207. In the second defrosting mode, the refrigerant circulation direction is returned to the positive direction, and the rotation of the fan 7 is slowed or stopped, or the operating frequency of the compressor 1 is increased, so that the temperature of the refrigerant to the drain pan 5 is increased.

The embodiments disclosed herein are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the claims rather than the description of the above embodiments, and is intended to include all modifications equivalent in meaning and scope to the claims.

Description of the reference numerals

1, a compressor; 2a first heat exchanger; 3 an expansion device; 4 a second heat exchanger; 5, a drain pan; 6, a heater; 7, a fan; 10. 210 a control device; 11. 12, 211, 212 control unit; 21. 22, 24, 25, 26, 28, 221, 222, 228, 229 tubes; 23. 27 an extension pipe; 30 temperature sensors; 41. 51 a processor; 42. 52 a memory; 43. 53 a communication interface; 100. 200 a refrigeration device; 101. 201 outdoor unit; 102. 202 indoor unit; 207 four-way valve.

Claims

1. A refrigeration device is provided with:

a refrigerant circuit that circulates a refrigerant in the order of a compressor, a first heat exchanger, an expansion device, and a second heat exchanger; and

a drain pan disposed below the second heat exchanger,

the cooling apparatus has, as operation modes, a cooling mode in which cooling is performed using the second heat exchanger, a first defrosting mode in which the second heat exchanger is heated, and a second defrosting mode in which the drain pan is heated.

2. The refrigeration device of claim 1,

the refrigeration device further includes:

a heater that heats the second heat exchanger; and

a fan that blows air to the first heat exchanger,

a refrigerant pipe connected between the first heat exchanger and the expansion device is configured to exchange heat with the drain pan,

in the first defrost mode, the heater operates,

in the second defrost mode, the heater is not operated,

the rotation speed of the fan in the second defrost mode is set to be lower than the rotation speed of the fan in the cooling mode.

3. The refrigeration device of claim 1,

the refrigeration device further includes:

a four-way valve that changes a circulation direction of the refrigerant in the refrigerant circuit to a reverse direction in which the refrigerant circulates in the order of the compressor, the second heat exchanger, the expansion device, and the first heat exchanger, the reverse direction being opposite to the forward direction; and

a fan that blows air to the first heat exchanger,

in the cooling mode, the four-way valve is set such that the circulation direction is the positive direction,

in the first defrosting mode, the four-way valve is set so that the circulation direction is the reverse direction,

in the second defrosting mode, the four-way valve is set so that the circulation direction becomes the positive direction,